Enzymatic detergent composition and method for degrading and removing bacterial cellulose

ABSTRACT

This invention relates to an enzymatic detergent drain cleaner composition containing: 
     0.015-20 wt % of an acid cellulase enzyme having hydrolytic activity specific to β-glucosidic bonds; 
     1-70 wt % of a water soluble carbonate salt; 
     1-70 wt % of a water soluble acid that reacts in an aqueous medium with the carbonate salt to form carbon dioxide that dissolves in the aqueous medium; 
     0.1-10 wt % of a surfactant; and 
     0.05-5 wt % of a thickening agent. This detergent composition may be used as an enzymatic detergent drain cleaner or in a method for removing or preventing bacterial cellulose deposits in an aqueous system at a solution temperature of up to about 60° C. and a pH of about 2 to about 7.

This application is a division of Ser. No. 08/610,946, filed Mar. 5,1996, now U.S. Pat. No. 5,783,537.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to compositions and methods for degrading,removing, and preventing bacterial cellulose deposits. Moreparticularly, this invention relates to enzymatic detergent compositionsand methods of using them to degrade, remove, and prevent polymericbacterial cellulose deposits in aqueous systems such as drain pipes.

2. Description of the Related Art

Traditional approaches to controlling or eliminating the problem ofbacterial cellulose build-up in sugar or alcohol enriched drain systemstypically have included contacting the cellulose with highly corrosivechemicals, such as concentrated hydrochloric acid, concentrated sulfuricacid, sodium hypochlorite, sodium silicate, chlorine bleach,phenylmercuric acetate, pentachlorophenol, tributyltin oxide,isocyanurates, or sodium hydroxide. However, these treatments haveproven ineffective or incapable of removing deposited-cellulosic slime,and they have several drawbacks associated with their use. Most of thesechemicals are toxic to many organisms, including humans. Their toxicitymakes them very dangerous during handling, and they contaminate andpollute if they are discharged into the environment. In addition to theproblems engendered by toxicity, many of these toxic and hazardouschemicals can damage the drain systems where bacterial cellulosedeposits are found.

Mechanical water jetting and rotor rooting are nontoxic alternatives tothe chemical treatments described above. Of these, water jetting ispreferred because it is less likely to cause damage to the drainsystems. Yet neither method is an effective, acceptable treatment toprevent or remove bacterial cellulose deposits in drain systems.Bacterial cellulose accumulates rapidly in susceptible drain systems,and to keep such drains completely clear by these mechanical meansrequires frequent treatments. The frequent interruption in drain serviceoccasioned by jetting or rooting makes them impractical. In addition,both methods involve significant manual labor, adding considerably tothe cost of removing the deposits. Their cost and inefficiency makejetting or rooting uneconomical as prophylactic treatments. The resultis that many drains having a bacterial cellulose problem areineffectively and infrequently treated and therefore function at aseverely reduced capacity or not at all.

U.S. Pat. No. 5,443,656 to Burrows et al. proposes a process fordegrading fibrous cellulose materials, more particularly toilet tissuein aqueous waste holding tanks, by contacting the material with acomposition comprising a cellulase enzyme, sodium bicarbonate, andcitric acid. However, this method does not use an enzyme having activityspecific to polymeric cellulose typically produced by microorganismssuch as Acetobacter bacteria, and the enzyme concentrations disclosedare too low for effectively treating cellulose deposited by suchmicroorganisms. Moreover, compositions disclosed in this referencecontain large quantities of sodium chloride, which drastically reducescellulase enzyme activity under the conditions wherein the presentinvention is applied.

U.S. Pat. No. 3,506,582 to Gertzman discloses enzymatic drain cleanercompositions composed of a metal salt of carbonic acid,glucono-delta-lactone, and a mixture of enzymes, including amylase,protease, lipase, pectinase, and cellulase. These compositions sufferthe same drawbacks found in the Burrows patent, i.e., they do notaddress the polymeric bacterial cellulose substrate produced bymicroorganisms such as Acetobacter bacteria, and they containsignificant amounts of sodium chloride, which inhibits enzyme activityunder the conditions where such bacterial cellulose deposits are found.Moreover, the disclosed compositions contain relatively highconcentrations of amylase and lipase enzymes specific to degradestarchy, greasy, or fatty materials rather than bacterial cellulose.

U.S. Pat. No. 5,264,146 to Tobiason discloses a method and compositionfor carrying sewer or drain cleaning agents, including lipase and lipaseexcreting bacteria, to clean draincs and sewer lines. This referenceneither discloses nor suggests using an enzyme having activity specificto the troublesome cellulose deposited in sugar and alcohol enrichedenvironments by microorganisms such as Acetobacter bacteria. Moreover,the disclosed compositions can contain other cleaning agents, includingcorrosive chemicals such as caustic soda and harmful solvents such asdichlorobenzene.

U.S. Pat. No. 5,407,595 to Kamiya discloses a detergent drain pipecleaning composition comprising a lipocatabolic lipase, an imbibingagent such as sodium bicarbonate, and an N-acyclic amino acid, but nocellulase enzyme. Thus, this composition also is not specific tocellulose produced by microorganisms such as Acetobacter bacteria, andtherefore is not effective to address the problem solved by the presentinvention.

SUMMARY OF INVENTION

The present invention relates to enzymatic detergent drain cleaners,compositions of matter, and methods for removing or preventing cellulosedeposits in aqueous systems produced by microorganisms such asAcetobacter bacteria. These drain cleaners, compositions and methods aresafe and economical, do not require the use of chemicals that arehazardous or toxic to humans and other life forms, decrease the risk ofenvironmental harm, and minimize ecological harm to the aqueous systemsrequiring removal or prevention of bacterial cellulose deposits.

Particularly, the present invention relates to drain cleaners andcompositions containing a biologically derived acid cellulase enzymepossessing hydrolytic activity specific to β-glucosidic bonds incellulose produced and deposited in aqueous systems by microorganismssuch as Acetobacter bacteria. The inventors have also discovered that byproviding the enzymatic detergent drain cleaners and compositions withan enriched dissolved carbon dioxide concentration or with a system forenriching the dissolved carbon dioxide concentration in the aqueoussystem being treated, the efficacy of the enzymatic hydrolysis ofcellulose is significantly increased. In the inventive methods, theenzymatic detergent drain cleaners and compositions are contacted withan aqueous system in need of removal or prevention of bacterialcellulose deposits for a sufficient time to allow at least partialhydrolysis of the bacterial cellulose, thereby effecting its easyremoval. The inventors also have discovered preferred systems forgenerating and enriching carbon dioxide, which systems also contributedetergent action to the claimed drain cleaners, compositions andmethods, and preferred surfactants and thickening agents that improvethe effectiveness of the claimed drain cleaners, compositions andmethods.

DETAILED DESCRIPTION OF THE INVENTION

Microbial cellulose is a floppy, slimy, gelatinous mass produced bymicroorganisms such as Acetobacter bacteria. This material appears innature when such bacteria come into contact with decomposing fruit orother sugar or alcohol enriched matter. Acetobacter bacteria thrive innatural or artificial sugar or alcohol enriched acidic environments,such as are found in flowers, fruits, leaves, saps, honey, vinegar,cider, wine, beer, syrups, fruit juices, and the like. Fermentation ofsugar by the Acetobacter bacteria results in a catalyzed biosynthesis ofcellulose fibrils, which accumulate around the bacteria cells.

For example, Acetobacter zymomonas will ferment sucrose to ethanol viaglucose within 8 to 12 hours of contacting the sucrose creating a highlysuitable medium for the continued development of this acetic acidbacterium. Glucose forms the repeating cellobiose sub-units ofcellulose, which is a β-1,4' polymer of D-glucose having β-glucosidiclinkages. The general reaction scheme is believed to be as follows:

    C.sub.12 H.sub.22 O.sub.11 (sucrose)→C.sub.6 H.sub.12 O.sub.6 (glucose)+C.sub.6 H.sub.12 O.sub.6 (fructose)

    C.sub.6 H.sub.12 O.sub.6 (glucose)→C.sub.2 H.sub.5 OH (ethanol)+CO.sub.2

    C.sub.2 H.sub.5 OH (ethanol)→CH.sub.3 COOH (acetic acid).

During fermentation, this acetic acid bacterium will begin to multiplyafter 2-3 days, utilizing the glucose or sucrose that are present in theearly stages of the fermentation.

The cellulose strand secreted by the acetic subspecies Acetobacterxylinium is a particularly unusual product. Under appropriateconditions, this Acetobacter will synthesize cellulose from glucose intoa ribbon of 0.05 to 0.1 μm diameter at a rate of approximately 2 μm perminute. The ribbons of this cellulose appear to polymerize andcrystallize into larger strands, which provide a floating mat orpellicle that furnishes the aerobic Acetobacter with a surface on whichto grow in an aqueous medium.

One particularly troublesome manifestation of polymeric bacterialcellulose occurs in sugar or alcohol enriched drain pipes such as areconnected to soft drink or beverage stations including alcoholicbeverage in food service, bar, and hotel establishments. Here, in thishighly favorable environment, Acetobacter bacteria and othercellulose-secreting microorganisms easily produce polymeric bacterialcellulose, which builds up in the drain pipes and ultimately can blockthe drain system. Presently, there are no suitable, effective, safe,non-polluting, and non-corrosive solutions to this problem.

The inventors have discovered enzymatic detergent drain cleaners andcompositions and methods of using them to prevent or remove polymericbacterial cellulose deposits produced in aqueous systems by Acetobacterbacteria. In a first embodiment, the enzymatic detergent drain cleanerof the present invention comprises an acid cellulase enzyme havinghydrolytic activity specific to the β-glucosidic bonds of bacterialcellulose, a water-soluble carbonate or bicarbonate salt, and a watersoluble acid that reacts with the carbonate salt in an aqueous medium toform carbon dioxide that dissolves in the aqueous medium. Preferably,this enzymatic detergent drain cleaner is prepared in dry form includinga surfactant and a thickener, which is conveniently storable in moisturebarrier package until use.

In a second embodiment, the composition of the present inventioncomprises an aqueous solution of an acid cellulase enzyme havinghydrolytic activity specific to the β-glucosidic bonds of bacterialcellulose and present in the aqueous solution an amount of at least0.015 g/l. This aqueous solution further has a dissolved carbon dioxideconcentration of at least 100 ppm at standard temperature and pressure.

In a third embodiment, the invention comprises a method wherein anaqueous system in need of removal or prevention of bacterial cellulosedeposits is contacted with an enzymatic detergent drain cleaner or acomposition of the present invention for a sufficient time to permit atleast partial hydrolysis of the bacterial cellulose, followed byremoving the partially hydrolyzed cellulose from the aqueous system.

The acidic cellulase enzyme specific to hydrolysis of the polymericcellulose produced by Acetobacter bacteria can be derived from certainstrains of Trichoderma reesei or Aspergillus niger, or their mutants orvariants either naturally or artificially induced. As used herein,Trichoderma reesei denotes microorganisms known by that name, as well asthose microorganisms classified under the names Trichodermalongibrachiatum and Trichoderma viride. Any cellulase enzyme or enzymecomplex that is specific to hydrolysis of cellulose produced byAcetobacter bacteria can be used.

A representative acid cellulase enzyme is the Cellulase Tr Concentratemulti-enzyme acid cellulase complex, which is commercially availablefrom Solvay Enzymes, Inc. Cellulase Tr Concentrate is a food gradecellulase complex obtained by controlled fermentation of a selectedstrain of Trichoderma reesei. This enzyme complex consists of bothexoglucanases and endoglucanases that directly attack native cellulose,native cellulose derivatives, and soluble cellulose derivatives. Thisenzyme complex specifically hydrolyzes the β-D,4-glucosidic bonds ofbacterial cellulose, in particular the polymeric bacterial celluloseproduced by Acetobacter bacteria, as well as its oligomers andderivatives.

Another representative cellulase enzyme commercially available fromSolvay Enzymes, Inc. is Cellulase TRL multi-enzyme liquid cellulasecomplex. Cellulase TRL cellulose enzyme complex is derived fromTrichoderma reesei in the same manner as Cellulase Tr Concentrate enzymecomplex, but is prepared and sold in liquid form. Its activity againstbacterial cellulose has been demonstrated to be equivalent to that ofCellulase Tr Concentrate enzyme complex.

Other suitable enzymes for use in the present invention includeCelluzyme Acid P enzyme and Celluclast 1.5L, both commercially availablefrom Novo Nordisk; Multifect™ Cellulase 300 enzyme, commerciallyavailable from Genencor International, and Rapidase® Acid Cellulaseenzyme, commercially available from Gist-Brocades International B.V.Still other cellulase enzymes or cellulase enzyme complexes are suitablefor use in the present invention, provided they exhibit specifichydrolytic activity directed at the β-glucosidic linkage characteristicof the polymeric bacterial cellulose produced by microorganisms such asAcetobacter bacteria.

Where the enzymatic detergent drain cleaners according to the presentinvention are prepared in dry form, i.e. exclusive of any water added toform a solution, but including any water normally complexed or boundwith dry ingredients, the acid cellulase enzyme should be present in anamount of about 0.015% to about 20% by weight, preferably about 0.05% toabout 15% by weight, more preferably about 0.5% to about 10% by weight,even more preferably from about 1% to about 8% by weight, still morepreferably from about 2% to about 7% by weight, and most perferably 6%by weight. Where the compositions according to the present invention areprepared as aqueous solutions, the acid cellulase enzyme concentrationin the solution should be at least about 0.015 g/l, preferably at leastabout 0.15 g/l, more preferably at least about 0.30 g/l, and still morepreferably at least about 0.60 g/l, and most preferably at least 0.85g/l.

It is to be understood by those of skill in the art that activities ofthe commercial acid cellulase enzymes recited above for use in thepresent invention may vary slightly from enzyme to enzyme, and that theassays and substrates of the assays used by the manufacturers of theseenzyme products to express their activity vary from manufacturer tomanufacturer. Nonetheless, it would be a matter of routineexperimentation to determine relative equivalents of each commercialenzyme preparation to be used in the present invention merely bychoosing one of the numerous cellulase assay methods known in the artand applying that method uniformly to the commercial preparations.

In the present drain cleaners, compositions and methods, the dissolvedcarbon dioxide, can be provided by any source, including carbon dioxidegas, carbon dioxide enriched water, and water containing carbon dioxidebut, is preferably derived from a system comprising a water-solublecarbonate salt and a water-soluble organic or inorganic acid that underaqueous conditions reacts with one another to generate dissolved carbondioxide in the aqueous medium. As used herein, the term carbonate saltdenotes both carbonate and bicarbonate salts and salts of carbonic acid.Accordingly, suitable water-soluble carbonate salts include lithiumcarbonate, lithium bicarbonate, sodium and potassium sesquicarbonate,sodium carbonate, sodium bicarbonate, ammonium carbonate, ammoniumbicarbonate, potassium carbonate, potassium bicarbonate, calciumcarbonate, calcium bicarbonate, magnesium carbonate, and magnesiumbicarbonate. Generally acceptable are the carbonate salts of alkalimetals (Group IA) and alkaline earth metals (Group IIA).

Any water-soluble organic or inorganic acid can be used in the presentinvention. Suitable organic acids include, but are not limited to,formic acid, acetic acid, hydroxy acetic acid, propionic acid, butyricacid, valeric acid, caproic acid, lauric acid, palmitic acid, stearicacid, citric acid, tartaric acid, succinic acid, malic acid, uric acid,gluconic acid or its precursor glucono-δ-lactone, polymaleic-acrylicacids, acrylic acids, polyacrylic acids, sebacic acid, maleic acid,benzoic acid, fumaric acid, isophthalic acid, terephthalic acid, subericacid, pimelic acid, malonic acid, glutaric acid, adipic acid, and lacticacid. Suitable inorganic acids include, but are not limited tohydrochloric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid,sulfuric acid, sulfamic acid, sulfurous acid, phosphoric acid,phosphorous acid, polyphosphoric acid, hypophosphorous acid, boric acid,sodium bisulfate, and sodium bisulfite.

Various combinations of acids and carbonate salts are suitable for usein the present invention. When dry drain cleaners are prepared accordingto the present invention, it is preferable to use salts and acids, aswell as the other product components, in powder form. Among thedisclosed acids, citric acid and sulfamic acid are preferred in anamount of about 10% to about 50% by weight. Citric acid is particularlypreferred, since in reacting with the carbonate or bicarbonate salt toform the present compositions, it forms citrate salts, which acts as a"builder" salt, softens the aqueous composition, and contributes adetergent action, further aiding with the decomposition and removal ofbacterial cellulose deposits. A particularly preferred combination ofacid and salt is citric acid in an amount of about 43% by weight of thecomposition, sodium carbonate in an amount of about 1% to about 10%,preferably about 5%, by weight of the composition, and sodiumbicarbonate in an amount of about 30% to about 50%, preferably about40%, by weight of the composition, wherein the sodium carbonate in partacts as a buffering agent and pH conditioner.

Where the drain cleaners according to the present invention are preparedin dry form, the water soluble carbonate salt and the water soluble acideach should be present in an amount of about 1% to about 70% by weight,preferably about 10% to about 50% by weight, more preferably about 13%to about 48% by weight, and most preferably about 15% to about 45% byweight. The carbonate salt and acid need not be present in equivalentamounts. The amount of each component necessary to generate a desiredconcentration of dissolved carbon dioxide gas can easily be calculatedby one of ordinary skill in the art based upon the stoichiometry of theingredients chosen and the conditions under which they are expected toreact.

Where the compositions according to the present invention are preparedin solution form, the amounts of carbonate salt and acid should bechosen to ensure a minimum dissolved carbon dioxide concentration of atleast 100 ppm, preferably at least about 300 ppm, more preferably atleast about 500 ppm, and most preferably at least about 1000 ppm.Without being bound by theory, it is believed that the enriched carbondioxide environment provided by the present invention mimics theenriched carbon dioxide environment in which the Acetobacter bacteriabiosynthesize polymeric bacterial cellulose, thereby creating anenvironment in which the activity of the cellulase enzyme is greatly andunexpectedly increased.

In preferred drain cleaners, compositions and methods of application,the carbon dioxide gas provides a forced thickened detergent foam, whichhelps fill the drain pipe environment in which polymeric cellulosedeposits typically are found with the enzymatic detergent foam, therebycoating as much as possible of the deposited cellulose with theenzymatic detergent or solution. Further, the carbon dioxide foam, as itslowly collapses, allows the drain cleaner or solution to have asubstantially increased contact time with the bacterial cellulose.Several substantially nonfoaming detergent formulations, wherebicarbonate salt was substantially or totally eliminated or replaced bysodium chloride or sodium sulfate, were found to be far less effectiveto degrade bacterial cellulose, even after 2 weeks long of soaking in abeaker test. By contrast, the detergent foams according to the presentinvention typically degrade bacterial cellulose completely down aftersoaking for about twenty-four hours in the beaker test.

In addition to the enzyme and carbon dioxide or carbon dioxidegenerating system, the drain cleaners and compositions of the presentinvention may also include an organic or inorganic thickening agent. Thethickener acts to cling the active ingredients to the cellulose surface,affording increased contact time and thereby enhancing the efficacy ofenzymatic degradation of cellulose.

The organic thickening agent of the present invention may be any of awide variety of organic thickening agents known to those skilled in theart. Particularly preferred are the crosslinked polyacrylic acid-typethickening agents, present in an amount of about 1% to about 5% byweight. As used herein, "polyacrylic acid-type" is intended to refer towater soluble homopolymers of acrylic acid or methacrylic acid orwater-dispersible or water-soluble salts, esters and amides thereof, orwater-soluble copolymers of these acids or their salts, esters or amideswith each other or with one or more ethylenically unsaturated monomers,such as styrene, maleic acid, maleic anhydride, 2-hydroxyethylacrylate,acrylonitrile, vinyl acetate, ethylene, propylene, or the like.

Preferably, the polyacrylic thickening agent is one of the crosslinkedpolyacrylic acid-type thickening agents commercially available from B.F.Goodrich under the CARBOPOL™ trademark. The CARBOPOL™ resins, also knownas carbomer resins, are hydrophilic, high molecular weight, crosslinkedacrylic acid polymers having an average equivalent weight of about 76and a general structure of the formula: ##STR1## The CARBOPOL™ resinsare crosslinked with a polyalkenyl polyether, such as a polyalkyl etherof sucrose having an average of 5.8 alkyl groups per molecule ofsucrose. Preferred thickening agents for the present invention includeorganic polymer thickening agents such as the Carbopol EZ-1™, CarbopolEZ-2™, and Carbopol EZ-ultra™ polymeric thickening agents, which arecommercially available from the BF Goodrich Company. Other suitablecarbomer thickening agents include the PNC carbomers sold commerciallyby 3V Inc.

Further suitable organic thickening agents include acrylic copolymerssuch as the Acusol® polymers sold commercially by Rohm & Haas Company,carboxyvinyl polymers such as the Neutragel™ and Polygel™ polymers soldcommercially by 3V Inc., polyacrylate polymers such as the Burco ThixPCS™ polymer sold commercially by Burlington Chemical Co., Inc., andpoly(methylvinylether/maleic) anhydride polymers such as Gantrez®polymer sold commercially by International Specialty Products.

Further examples of suitable organic thickeners which can be used in thepresent invention include Guar gum sold as "Supercol" by Aqualon, Guarhydroxy propyltrimonium chloride sold as "Hi-Care 1000" by Alcolac, cornstarch, and urethane associative thickeners sold as "NOPCO" by HenkelCorporation.

Still other suitable organic thickeners include fatty acid thixotropicthickeners such as higher aliphatic fatty monocarboxylic acids havingfrom about 8 to about 22 carbon atoms, inclusive of the carbon atom ofthe carboxyl group of the fatty acid. The aliphatic radicals aresaturated and can be straight or branched. Mixtures of fatty acids maybe used, such as those derived from natural sources, such as tallowfatty acid, coco fatty acid, soya fatty acid, etc., or from syntheticsources available from industrial manufacturing processes.

Examples of the fatty acids which can be used as thickeners include, forexample, decanoic acid, lauric acid, dodecanoic acid, palmitic acid,myristic acid, stearic acid, oleic acid, eicosanoic acid, tallow fattyacid, coco fatty acid, soya fatty acid and mixtures of these acids. Themetal salts of the above fatty acids can also be used in the presentinvention as thixotropic thickener agents, such as salts of themonovalent and polyvalent metals such as sodium, potassium, magnesium,calcium, aluminum and zinc.

Many of the metal salts are commercially available. For example, thealuminum salts are available in the triacid form, e.g., aluminumstearate as aluminum tristearate, Al(OCOC₁₇ H₃₅)₃. The monoacid salts,e.g., aluminum monostearate, Al(OH)₂ (OCOC₁₇ H₃₅ ) and diacid salts,e.g. aluminum distearate, Al(OH)(OCOC₁₇ H₃₅)₂, and mixtures of two orthree of the mono-, di- and triacid salts can be used for those metals,e.g. Al, with valences of +3, and mixtures of the mono- and diacid saltscan be used for those metals, e.g. Zn, with valences of +2.

The thickening agent used in the present invention also may be any oneof a number of natural or synthetic inorganic materials, such as clays,silicas, aluminas, titanium dioxide (pyrogenic) and calcium and/ormagnesium oxides. All of these materials are readily available fromcommercial sources.

Various types of clays which are useful include kaolins such askaolinite, dicktite, nacrite, halloysite and endillite; serpentine clayssuch as chrysotile and amesite; smectites such as montmorillonite(derived from bentonite rock), beidellite, nontronite, hectorite,saponite and sauconite; illites or micas; glauconite; chlorites andvermiculites; attapulgite and sepiolite. Mixed layer clays exhibitingintercalation of mineral sandwiches with one another may be used, suchas, for example, mixed-layer clay mineral sheets of illite interspersedrandomly or regularly with montmorillonite, or chlorite with one of theother types of clay, such as vermiculite. Other useful clays includeamorphous clays, such as allophane and imogolite, and high-alumina clayminerals such as diaspore, boehmite, bibbsite and cliachite. Varioustypes of silicas which are useful include diatomite, precipitated silicaand fumed silica. Various types of aluminas may be used, as well asvarious types of calcium and magnesium oxides.

Suitable smectite thickening agents include the Aquamont, Gelwhite®, andMineral Colloid™ montmorillonite thickeners commercially sold bySouthern Clay Products, the Bentolite® bentonite thickener commerciallysold by Southern Clay Products, the Bentone EW and Bentone LT hectoritethickeners commercially sold by Rheox, Inc., and the Laponite® hectoritethickener commercially sold by Southern Clay Products. Other acceptableinorganic thickeners include attapulgite clays, such as the Attagelattapulgite thickeners commercially sold by the Engelhard Minerals andChemicals Corporation. Still other acceptable inorganic thickenersinclude fumed silicas, such as the Aerosil® fumed silicas soldcommercially by Degussa Corporation and the Cab-O-Sil® and Cab-O-Sperse®fumed silicas sold commercially by Cabot Corporation, and silicondioxides, such as Sipernat 22LS silicon dioxide sold commercially byDegussa Corporation Pigments Division. The thickening agent of theinvention also can be selected from a group of complex magnesiumaluminum silicates derived from natural smectite clays by a proprietaryrefining process and sold by R. T. Vanderbilt Company, Inc. under thetrademarks VEEGUM® and VAN GEL®.

Where the enzymatic detergent drain cleaners according to the presentinvention are prepared in dry form, the thickener should be present inan amount of at least about 0.05% to about 5% by weight, preferably atleast about 0.1% to about 4% by weight, more preferably at least about0.5% to about 3%, and most preferably at least about 1% to about 2%.Where the compositions of the present invention are prepared in solutionform, the thickener should be present in a concentration of at leastabout 0.01 g/l, preferably at least 0.15 g/l, more preferably at leastabout 0.20 g/l, and most preferably at least about 0.30 g/l.

The drain cleaners and compositions of the present invention also mayinclude a surfactant which assists in the formation of a thickened foamwith the carbon dioxide gas. A wide variety of surfactants can be usedin the present invention, selected from nonionic, cationic, anionic, oramphoteric surfactants.

Examples of nonionic surfactants that can be employed are alkoxylatedalkyl phenols, amides, amines, ethoxylated or propoxylated higheraliphatic alcohols, alkyl polyglucosides, alkyl polysaccharides andsulfonamides. These well known surfactants include sorbitan esters ofC₁₀ to C₂₂ fatty acids, polyoxyethylene sorbitan esters of C₁₀ to C₂₂fatty acids, polyoxyethylene sorbitol esters of C₁₀ to C₂₂ fatty acids,polyoxyethylene derivatives of C₆ to C₂₀ fatty phenols, andpolyoxyethylene condensates of C₁₀ to C₂₂ fatty acids or fatty alcohols.Polyoxyethylene and polyoxypropylene analogs of the above surfactantsalso can be used in the present invention.

Commercially available nonionic surfactants suitable for use in thisinvention are Shell Neodol™ 91-6 and Shell Neodol™ 91-2.5 surfactants.Neodol™ 91-6 surfactant is a polyethylene glycol ether of a mixture ofsynthetic C₉₋₁₁ fatty alcohols with an average of 6 moles of ethyleneoxide. Neodol™ 91-2.5 surfactant is an ethoxylated alcohol of a mixtureof synthetic C₉₋₁₁ fatty alcohols with an average of 2.5 moles ofethylene oxide.

Other useful nonionic surfactants available from Shell are the Neodol25-7 and Neodol 25-6.5 surfactants. The former is a condensation productof a mixture of higher fatty alcohols averaging about 12 to 15 carbonatoms, with about 7 moles of ethylene oxide and the latter is acorresponding mixture wherein the carbon atom content of the higherfatty alcohol is 12 to 15 and the number of ethylene oxide groupspresent averages about 6.5. The higher alcohols are primary alkanols.Other examples of such detergents include Tergitol® 15-S-7 and Tergitol®15-S-9 surfactants, both of which are linear secondary alcoholethoxylates made by Union Carbide Corp. The former is a mixedethoxylation product of 11 to 15 carbon atoms linear secondary alkanolwith seven moles of ethylene oxide and the latter is a similar productbut with nine moles of ethylene oxide being reacted.

Another suitable nonionic surfactant is available from Union CarbideCorporation under the trademark Tergitol® MDS-42. This nonionicsurfactant is a C₁₂ -C₁₄ linear alcohol containing 55% by weight randomdistributed oxyalkyl groups of which 42% are ethoxy and 58% propoxygroups. Another nonionic surfactant that can be used is Alfonic 18-57surfactant, made by Vista Chemical Company. Other useful nonionicsurfactants are the Poly-Tergent S-LF surfactants available from OlinCorporation. These surfactants are alkoxylated linear fatty alcohols.Surfactants of this type are available under the tradenames Poly-TergentS-LF 18, Poly-Tergent S-305-LF, Poly-Tergent S-405-LF and Poly-TergentCS-1. Another liquid nonionic surfactant that can be used is sold underthe tradename Lutensol SC 9713.

Synperonic nonionic surfactant from ICI such as LF/D25 surfactant arenonionic surfactants that can be used in the detergent compositions ofthe instant invention. Also useful in the present compositions arehigher molecular weight nonionic surfactants, such as Neodol 45-11surfactant by Shell, which are similar ethylene oxide condensationproducts of higher fatty alcohols, with the higher fatty alcohol beingof 14 to 15 carbon atoms and the number of ethylene oxide groups permole being about 11. Such products are also made by Shell ChemicalCompany.

Still other examples of suitable nonionic surfactants includepolyoxyethylene and/or polyoxypropylene condensates of aliphaticcarboxylic acids, aliphatic alcohols and alkyl phenols; polyoxyethylenederivatives of sorbitan mono-,di-, and tri-fatty acid ester andpolyoxyethylenepolyoxypropylene block polymers.

Further examples of suitable nonionic surfactants includealkylpolyglucoside surfactants such as disclosed in U.S. Pat. No.5,169,553, the disclosure of which is incorporated herein by reference.These surfactants are derived from corn starch, a cellulose withα-linkages between glucose units, and coconut oil.

Still other examples of suitable nonionic surfactants includealkylpolysaccharide surfactants such as disclosed in U.S. Pat. No.5,169,553, the disclosure of which is incorporated herein by reference.

Other suitable nonionic surfactants include ethoxylated propoxylatedfatty alcohols, which are possibly capped, characterized by the presenceof an organic hydrophobic group and an organic hydrophilic group andtypically produced by the condensation of an organic aliphatic or alkylaromatic hydrophobic compound with ethylene oxide and/or, propyleneoxide (hydrophilic in nature). Practically any hydrophobic compoundhaving a carboxy, hydroxy, amido or amino group with a free hydrogenattached to the nitrogen or oxygen can be condensed with ethylene oxideor with the polyhydration product thereof, polyethylene glycol, to forma nonionic detergent. The length of the hydrophilic or polyoxyethylenechain can be readily adjusted to achieve the desired balance between thehydrophobic and hydrophilic groups.

The useful nonionic surfactants also include polyalkoxylated lipophileswherein the desired hydrophile-lipophile balance is obtained fromaddition of a hydrophilic poly-lower alkoxy group to a lipophilicmoiety. Examples include poly-lower alkoxylated higher alkanols whereinthe alkanol is of 9 to 18 carbon atoms and wherein the number of molesof lower alkylene oxide (of 2 or 3 carbon atoms) is from 3 to 12.

Useful nonionic surfactants are represented by the Plurafac series fromBASF Chemical Company which are the reaction product of a higher linearalcohol and a mixture of ethylene and propylene oxides, containing amixed chain of ethylene oxide and propylene oxide, terminated by ahydroxyl group. Examples include a C₁₃ -C₁₅ fatty alcohol, condensedwith 7 moles propylene oxide and 4 moles ethylene oxide, and a C₁₃ -C₁₅fatty alcohol, condensed with 5 moles propylene oxide and 10 molesethylene oxide. Acceptable commercial products include the PlurafacLF132 and Plurafac LF231 surfactants sold by BASF. Other suitablenonionic surfactants include sorbitol monolaurate propylene oxidecondensates, sorbitol monomyristate propylene oxide condensates,sorbitol monostearate propylene oxide condensates, dodecyl phenolpropylene oxide condensates, myristyl phenol propylene oxidecondensates, octyl phenyl propylene oxide condensates, nonyl phenylpropylene oxide condensates, stearyl phenol propylene oxide condensates,lauryl alcohol propylene oxide condensates stearyl alcohol propyleneoxide condensates, secondary alcohol propylene oxide condensates such asC₁₄ -C₁₅ secondary alcohols condensed with propylene oxide, sorbitantristearate condensed with propylene oxide, sorbitan trioleate condensedwith propylene oxide, and sorbitan trioleate.

Anionic surfactants useful in this invention generally include alkalimetal, ammonium and magnesium salts of alpha olefin sulfonates, alkylsulfonates, alkyl aryl sulfonates, alkyl aryl ether sulfates, alkylether sulfates, sulfated alcohol ethoxylates, taurates, petroleumsulfonates, alkyl napthalene sulfonates, alkyl sarcosinates and thealkyl sulfosuccinates.

Anionic surfactants useful in the present invention are the linear orbranched alkali metal mono- and di(C₈₋₁₄)alkyl diphenyl oxide mono- anddisulfonates, commercially available from Dow Chemical, for example asthe DOWFAX™ 3B-2 and DOWFAX™ 2A-1 surfactants. Other suitablesurfactants include the primary alkylsulfates, alkylsulfonates,alkylarylsulfonates, sec-alkylsulfates and olefin sulfonate. Examplesinclude sodium C₁₀ -C₁₈ alkanesulfonates such as sodium laurylsulfonate, sodium hexadecylsulfonate, sodium dodecyl sulfate, sodium andtallow alcohol sulfate, and sodium C₁₂ -C₁₈ alkylbenzenesulfonates suchas sodium dodecylbenzenesulfonates. The corresponding potassium andmagnesium salts may also be employed.

Specific anionic surfactants useful in this invention include sodiumlauryl sulfonate, ammonium lauryl sulfonate, dodecyl benzene sulfonate,sodium lauryl ether sulfate, diethanolamine lauryl sulfate, ammoniumsalts of sulfated alcohol ethoxylates, sodium cocoyl isethionate, sodiumN-methyl-N-oleoyl taurate, sodium N-methyl-N-cocyl taurate,triethanolamine lauryl sulfate, disodium monooleamide PEG-2sulfosuccinate, petroleum sulfonates sodium salt, alkyl napthalenesodium sulfonates, sodium lauroyl sarcosinate, and sodium alkylsulfosuccinate. Other useful anionic surfactants include sodium orpotassium dodecyl sulfate, sodium trioleate, sodium or potassium stearylsulfate, sodium or potassium dodecyl benzene sulfonate, sodium orpotassium stearyl sulfonate, triethanol amine salt of dodecyl sulfate,sodium laurate, sodium or potassium myristate, and sodium or potassiumstearate. Sodium dodecyl benzene sulfonate powder, sold by StepanChemical Company as Nacconol 90G surfactant, is preferred.

Other suitable surfactants useful herein include the amine oxidesurfactants of the structure R₂ R₁ NO in which R₂ and R₁ each representsa lower alkyl group, for instance, a lower alkyl, or a long chain alkylgroup having from 8 to 22 carbon atoms, for instance a lauryl, myristyl,palmityl or cetyl group. Instead of an amine oxide, a correspondingsurfactant phosphine oxide R₂ R₁ PO or sulfoxide R₂ R₁ SO can beemployed. Betaine surfactants are typically of the R₃ R₄ N⁺ R₅ COO⁻, inwhich R₃ and R₄ each represents a lower alkylene group having from 1 to5 carbon atoms and R₅ represents a long chain alkyl group having from 8to 22 carbon atoms. Specific examples of the amino oxide surfactants arelauryldimethylamine oxide, myristyldimethylamine oxide, thecorresponding phosphine oxides and sulfoxides, and the correspondingbetaines, including dodecyldimethylammonium acetate,tetradecyldiethylammonium pentanoate, hexadecyldimethylammoniumhexoanoate and the like.

Cationic surfactants useful in this invention include, e.g., thequaternary ammonium surfactants such as C₁₀ to C₂₂ fatty ammoniumcompounds having 10 to 22 carbon atoms, C₁₀ to C₂₂ fatty morpholineoxides, propylene oxide condensates of C₁₀ to C₂₂ fatty acid monoestersof glycerins, the mono- or diethanol amides of C₁₀ to C₂₂ fatty acids,and alkoxylated siloxane surfactants containing ethylene oxide unitsand/or propylene oxide units. As is known in the surfactant art, thecounter ion for quaternary ammonium surfactants is usually a halide,sulfate, or methylsulfate, the chlorides being the most commonindustrially available compounds.

Other suitable cationic surfactants suitable for use in the presentinvention include straight chain alkyl fatty amines, quaternary ammoniumsalts, alkyl-substituted quaternary ammonium salts,alkylaryl-substituted quaternary ammonium salts, quaternaryimidazolinium salts, amine oxides, fatty amine oxides, tri-fatty amineoxides, tri-quaternary phosphate esters, amphoglycinate phosphates,amine acetates, long chain amines and their salts, diamines and theirsalts, polyamines and their salts, polyoxyethylenated long chain amines,and quaternized polyoxyethylenated long chain amines.

Specific cationic surfactants useful in the present invention includedecyldimethyl amine oxide, cocoamidodimethyl amine oxide,trimethyldodceylammonium chloride, and trimethylstearylammoniummethylsulfate. Suitable, commercially available cationic surfactantsinclude the surfactant sold under the trademark Q-17-2™ and the AO-3,8™surfactant by the Exxon Chemical Company, Varisoft™ 222 and Arosurf™TA-100 surfactants by the Witco Chemical Company, and Ninox L™surfactant by the Stepan Chemical Company. Q-17-2™ surfactant by theExxon Chemical Company is a 75% by weight aqueous solution ofisotridecyloxypropyl dihydroxyethylmethylammonium chloride. The ExxonAO-3,8™ surfactant is a proprietary tertiary eight-carbon amine oxide.The Varisoft™ 222 surfactant is a diamidoamine-based quaternary with aformula of methylbis(tallow amidoethyl)2-hydroxyethyl-ammonium methylsulfate. The Arosurf™ TA-100 surfactant is a dialkyldimethyl quaternarywith the chemical composition of distearyldimethylammonium chloride. TheNinox-L™ surfactant is a lauryldimethyl amine oxide.

Amphoteric surfactants useful in this invention generally includebetaines, sultaines, imidazoline derivatives and the like. Specificamphoteric surfactants useful in this invention includericinoleamidopropyl betaine, cocamidopropyl betaine, stearyl betaine,stearyl amphocarboxy glycinate, sodium lauraminopro-pionate,cocoamidopropyl hydroxy sultaine, disodium lauryliminodipropionate,tallowiminodipropionate, cocoampho-carboxy glycinate, cocoimidazolinecarboxylate, lauric imidazoline monocarboxylate, lauric imidazolinedicarboxylate, lauric myristic betaine, cocoamidosulfobetaine,alkylamidophospho betaine and the like. Other useful amphotericsurfactants include decyl amino betaine; coco amido sulfobetaine, oleylamido betaine, coco imidazoline, coco sulfoimidazoline, cetylimidazoline, 1-hydroxyethyl-2-heptadecenyl imidazoline, 1-hydroxyethyl-2mixed heptadecenyl heptadecadienyl imidazoline, and n-coco morpholineoxide. Suitable, commercially available amphoteric surfactants includeMiranol™ FBS surfactant by Rhone-Poulenc and Mackalene™ 316 surfactantby McIntyre Chemical Company. The Miranol™ FBS surfactant is a 39% byweight aqueous solution of disodium cocoampho dipropionate. TheMackalene™ 316 surfactant is a stearamidopropyl dimethylamine lactate.

Any combination of nonionic, cationic, anionic, or amphotericsurfactants can be used in the present invention. It may be preferablein certain embodiments of the present invention to include a mixture ofsurfactants. In all embodiments, the surfactant selected should beeffective to enhance formation of a thickened foam with the dissolvedcarbon dioxide gas. Where the enzymatic detergent drain cleaners of thepresent invention are prepared in dry form, the surfactant should bepresent in an amount of at least about 0.1% to about 10% by weight,preferably about 0.5% to about 8% by weight, more preferably about 1% toabout 6% by weight, and most preferably about 2% to about 5% by weight.Where the compositions of the present invention are in solution form,the surfactant should be present in the solution in a concentration ofat least about 0.05 g/l, preferably at least about 0.25 g/l, morepreferably at least about 0.50 g/l, and most preferably at least about1.0 g/l.

The effective pH range of the present drain cleaner and composition isabout 2.0 to about 7.0, preferably about 3.5 to about 6.5, and morepreferably about 4.0 to about 5.5. Maintenance of the pH within theseranges is accomplished by providing, if necessary, any of the pHconditioners and buffering agents well known to the art and compatiblewith the other elements of the drain cleaner or composition.

The effective temperature range is up to about 60° C. (140° F.),preferably about 40° to about 55° C., and more preferably about 40° toabout 50° C. (about 104° to about 122° F.).

The method of the present invention generally comprises contacting anaqueous system in need of bacterial cellulose removal or prevention withthe present enzymatic detergent drain cleaners or compositions underaqueous conditions for a sufficient time to at least partially hydrolyzethe bacterial cellulose, whereby the at least partially hydrolyzedmaterial is removed from the aqueous system.

The method of the present invention requires no particular mode ofcontacting the enzymatic drain cleaner or composition with the cellulosedeposit desired to be removed, provided the contact takes place for atime sufficient to allow at least partial hydrolysis, such that thecellulosic materials can be removed with minimal mechanical or manualeffort, such as by flushing or rinsing with tap water, by gentlemechanical agitation, or by continued use of the aqueous system beingtreated. Preferably, the drain cleaner or composition is permitted tocontact the deposits for at least two to three hours. When the presentdrain cleaners or compositions have sufficient contact time with thedeposits, hydrolysis will result in production of water soluble glucose,and its oligomers which is easily rinsed without any mechanical actionneeded.

The drain cleaners, compositions, and methods of the present inventioncan be applied to effect both prevention and removal of bacterialcellulose deposits. When used to clean drain pipes, such as soft drinkand alcoholic beverage station drain pipes, the condition of the drainmust be ascertained, i.e. whether the drain is fully or partiallyclogged. If fully clogged, the drain can be partially unblocked,typically by mechanical means such as snaking, rotor rooting, waterjetting, etc., to allow the enzymatic detergent drain cleaner orcomposition to contact as much of the deposited cellulose as possible.

In one embodiment of the present method used to remove or preventbacterial cellulose in an aqueous drain system, a dry enzymaticenzymatic detergent drain cleaner according to the present invention isadded directly to a drain system through an opening in the system, suchas a floor drain or any other opening that will allow access to thedrain interior. Following addition of the dry product to the drain, anaqueous solution of the drain cleaner is formed in the drain by addingan aqueous medium to the drain. Preferably, the aqueous medium is hot,up to about 60° C., preferably between about 40° and about 55° C., andmore preferably between about 40° and about 50° C. The resultant aqueousenzymatic solution is allowed to disperse throughout the drain system,where it contacts the bacterial cellulose deposits.

In a preferred method, the drain system is substantially closed afterthe dry composition is added but before the aqueous medium is added.Upon addition of the aqueous medium, the carbonate salt and acid reactto form carbon dioxide, and the resultant pressure buildup in the drainin the vicinity of the reaction forces the enzymatic solution throughoutthe drain system and into contact with the deposited bacterialcellulose.

In another embodiment of the present method, the dry enzymatic draincleaner of the present invention is mixed with a hot aqueous medium in avessel to form a composition comprising an aqueous enzymatic solution,which is simply added to an aqueous system in need of removal orprevention of bacterial cellulose deposits. In a more preferred methodfor use in treating aqueous drain systems, the vessel is the reservoirof a hand-held liquid spray apparatus, such as the Spray Doc® pressuresprayer with spray tip removed, manufactured by the GilmourManufacturing Co., Somerset, Pa. The resultant enzymatic solution isthen applied with the spray apparatus in accordance with themanufacturer's instructions directly to the drain system in need oftreatment.

The following examples are illustrative only, and are not intended tolimit or otherwise circumscribe the claimed invention. One skilled inthe art can make, without undue experimentation, various insubstantialsubstitutions and variations by equivalent means, without departing fromthe spirit or teaching of this invention. Similarly, although preferredembodiments of the invention are described herein in detail, one ofskill in the art can make variations to those embodiments withoutdeparting from the spirit of the invention or the scope of the claims.

EXAMPLE 1 PREPARATION OF POWDERED ENZYMATIC DETERGENT DRAIN CLEANER

A powdered enzymatic detergent drain cleaner product can be prepared inany suitable mixing device. For example, a twin-shelled or Hobert mixercan be used, but a ribbon mixer also is suitable. Desired amounts ofcitric acid, sodium carbonate, powdered Nacconol 90G surfactant, sodiumbicarbonate, Carbopol thickener, and Cellulase Tr Concentrate wereweighed and set aside. The mixer was charged with the citric acid andsodium carbonate, which were mixed several minutes. When these twoingredients are thoroughly mixed, the Nacconol surfactant was added andallowed to mix for several more minutes, followed by the sodiumbicarbonate addition and several more minutes of mixing. Next theCarbopol thickener was added and allowed to mix, followed by theCellulase Tr Concentrate enzyme. All the ingredients having been added,the mixture was allowed to mix for at least five minutes until afree-flowing powder was obtained. The above order of addition is notcritical to the function of the product, but avoids dust formationduring the mixing procedure.

EXAMPLE 2 ENZYMATIC DETERGENT DRAIN CLEANER FORMULATIONS

The following are examples of dry compositions prepared according to thepresent invention. All amounts are expressed as weight percentages.

    ______________________________________                                        Ingredients                                                                           102-34-8 102-34-9 102-34-10                                                                            102-51-4                                                                             102-32-3                              ______________________________________                                        Sulfamic                                                                              40       20       --     --     38                                      Acid                                                                          Citric Acid -- 20 40 43  8                                                    Sodium 40 40 40 40 34                                                         Bicarbonate                                                                   Sodium  5  5  5  5  5                                                         Carbonate                                                                     Nacconol 10 10 10  5  6                                                       90G                                                                           Carbopol  1  1  1  1  3                                                       EZ-2                                                                          Cellulase Tr  4  4  4  6  6                                                   Concentrate                                                                    100% 100% 100% 100% 100%                                                   ______________________________________                                    

EXAMPLE 3 NON-FOAMING ENZYMATIC DRAIN CLEANER

The following Table compares a dry enzymatic detergent drain cleanerformulation of a foaming cleaner prepared according to this invention(102-44-0) with three non-foaming cleaners (102-46-2, 102-46-3, and102-46-4), wherein the sodium bicarbonate was replaced with sodiumchloride (102-46-2), sodium sulfate (102-46-3), or additional citricacid and sodium citrate.

    ______________________________________                                        Ingredients 102-44-0 102-46-2  102-46-3                                                                             102-46-4                                ______________________________________                                        Citric Acid 40       20        20     35                                        Sodium Citrate --  20 20 35                                                   Sodium Carbonate  5  5  5 10                                                  Sodium 40 -- -- --                                                            Bicarbonate                                                                   NaCl -- 40 -- --                                                              Na.sub.2 SO.sub.4 -- -- 40 --                                                 Nacconol 90G 10 10 10 10                                                      Carbopol EZ-1  1  1  1  2                                                     Cellulase Tr  4  4  4  8                                                      Concentrate                                                                    100% 100% 100% 100%                                                        ______________________________________                                    

Performance of Formulations 102-46-2 and 102-46-3 was very poor onhydrolysis of bacterial cellulose. Very little degradation occurred evenafter two weeks of soaking cellulose with these formulations, whereaswith formula 102-44-0, complete degradation occurred with overnighttreatment. Performance of Forumulation 102-46-4 is acceptable, butslightly slower than Formulation 102-44-0.

EXAMPLE 4 Carbon Dioxide Solubility Calculations

Objective

To determine the amount of carbon dioxide (CO₂) gas in both the liquidphase and the gas phase when solutions of enzymatic detergent draincleaner according to the present invention are prepared at variousconcentrations and temperatures.

Theory

Reaction of the dry product components in water in a closed containerproduces carbon dioxide, which exerts a measurable pressure on thecontainer walls. Where the dry formulation comprises citric acid, sodiumbicarbonate, and sodium carbonate to form the carbon dioxide, thegeneral reaction scheme is as follows:

    C.sub.6 H.sub.8 O.sub.7 +NaHCO.sub.3 +Na.sub.2 CO.sub.3 →Na.sub.3 C.sub.6 H.sub.5 O.sub.7 +2CO.sub.2 +2H.sub.2 O Citric Acid

The total pressure exerted on the container walls is the sum of threepartial pressures: atmospheric pressure; water pressure (P_(water)); andcarbon dioxide pressure (P_(carbon) dioxide). Because the atmosphericpressure is equal both inside and outside the container, the gaugepressure of the vessel measures the sum (P_(Total)) of the partialpressures of water and carbon dioxide. Thus, according to Dalton's Law,

    P.sub.Total =P.sub.water +P.sub.carbon dioxide.

Under the conditions of this trial (high specific volume and dilute gassolution), both the Ideal Gas relation and Henry's Law are valid andthus can be used to calculate the amount of carbon dioxide gas dissolvedin the liquid solution. The vapor pressure of water at system conditionsis determined by the Antoine equation and is available from, forexample, Perry's Chemical Engineering Handbook or the CRC Handbook ofChemistry and Physics.

Experimental Procedure

For the closed system, a pressure sprayer having a 12 liter capacity(Model 301P by the Gilmour Mfg. Co.) was modified by removing the spraynozzle from the delivery tube and replacing it with a liquid dampened,factory calibrated, 0-30 psig pressure gauge (Ametek, U.S. GaugeDivision). Powdered enzymatic detergent drain cleaner was preparedaccording to formula 102-51-4 in Example 2 and weighed into one ounce,two ounce, three ounce, four ounce, and six ounce samples. Afterweighing, the samples were sealed in water-soluble polyvinyl alcoholfilm packages.

Prior to each run, the container was washed thoroughly with one to twogallons of detergent solution (approximately 1 oz./gal.) and rinsedthoroughly three times with tap water. After cleaning, the container wascharged with four liters of tap water heated to a specified temperature,leaving eight liters of head space. The desired packaged amount of dryproduct was dropped into the charged container, and the pump/capassembly was fastened and sealed tightly onto the container.

After charging and sealing, the container was shaken for about fiveseconds at half-minute intervals while the dispenser valve was heldopen, until the PVA package broke, its contents reacted, and theinternal pressure of the container stabilized. Stabilization wasdetermined when three consecutive identical readings were obtained atone minute intervals. After the stabilized pressure was recorded, thecontainer was emptied, cleaned, and rinsed to prepare it for the nextrun.

Sample Calculation

Using the recorded gauge pressure, the carbon dioxide concentration inthe liquid and gas phases was calculated. The following is a samplecalculation for Experiment No. 6 in the Table that follows, wherein twoounces of dry product is dissolved in four liters of tap water at 110°F.

When reacted under aqueous conditions, 100 g of formula 102-51-4 willproduce 0.5704 moles or 12.78 liters of carbon dioxide gas at standardtemperature and pressure (0° C. and 760 mm Hg; STP). Thus, two ounces(56.70 g) will produce 7.25 liters (0.32 moles) irn an eight litervolume (the head space in the container; V_(Exp)). This volume of gaswill cause some of the carbon dioxide to be dissolved in the liquid(solution) phase.

Assuming X to be the volume of gas in liters at STP dissolved into theliquid phase, then (7.25-.sub.χ) liters (V_(STP)) of carbon dioxideremain in the gas phase. The partial pressure of water (P_(water)) at110° F. (T_(Exp)) is 65.82 mm Hg (CRC Handbook). The measured stabilizedpressure (P_(Total)) was 9.5 psig, or 491.16 mm Hg. Using the Ideal GasLaw, the partial pressure of carbon dioxide at experimental conditions(P_(carbon) dioxide) can be expressed thus: ##EQU1##

The following Table summarizes the results obtained for amounts of dryproduct varying from one to six ounces dissolved in four liters of hotwater at temperatures ranging from 110° F. to 138° F.

    __________________________________________________________________________    Formulation 102-51-4, Packaged in Sealed Water Soluble PVA Film                 CO.sub.2 Gas Generated in The Pressurized Closed Dispenser From             Dissolution of Powdered Detergent                                             __________________________________________________________________________    Experi-                Temperature of                                                                          Theoretical                                                                           Total Theoretical                      ment Amount of Temperature of Detergent Moles of CO.sub.2 Amount of                                                  CO.sub.2                               Sequence Detergent Used Water Used Solution Produced at STP Produced at                                              STP                                  __________________________________________________________________________      1. 1 oz. (28.35 g) 138° F. (58.89° C.) 126° F.                                                  (52.22° C.) 0.16M 3.62 L                                                2. 3 oz. (85.05 g) 138°                                               F. (58.89° C.) 126°                                              F. (52.22° C.)** 0.49M                                                10.87 L                                3. 6 oz. (170.10 g) 138° F. (58.89° C.) 126° F.                                                 (52.22° C.) 0.97M 21.73 L       4. 4 oz. (113.40 g)*** 120° F. (48.89° C.) 110° F.                                              (43.33° C.) 0.65M 14.49 L       5. 1 oz. (28.35 g) 120° F. (48.89° C.) 110° F.                                                  (43.33° C.) 0.16M 3.62 L                                                6. 2 oz. (56.70 g) 120°                                               F. (48.89° C.) 110°                                              F. (43.33° C.) 0.32M                                                  7.25 L                                 7. 3 oz. (85.05 g) 120° F. (48.89° C.) 110° F.                                                  (43.33° C.) 0.49M 10.87 L       8. 4 oz. (113.40 g) 120° F. (48.89° C.) 110° F.                                                 (43.33° C.) 0.65M 14.49 L       9. 6 oz. (170.10 g) 120° F. (48.89° C.) 110° F.                                                 (43.33° C.) 0.97M 21.73 L       10. 1 oz. (28.35 g) 110° F. (43.33° C.) 102° F.                                                 (38.89° C.) 0.16M 3.62 L                                                11. 3 oz. (85.05 g) 110°                                              F. (43.33° C.) 102°                                              F. (38.89° C.) 0.49M                                                  10.87 L                                12. 6 oz. (170.1 g) 110° F. (43.33° C.) 102° F.                                                 (38.89° C.) 0.97M 21.73       __________________________________________________________________________                                             L                                         Known Water Vapor       Calculated (from                                                                         Calculated (from                         Pressure at Total Experimental Experimental Amount of Experimental)                                                 Experi- Solution Pressure*                                                   CO.sub.2 Remained in The Amount                                               of CO.sub.2                             ment Temperature Produced at Ambient Gas Phase in 8L Head Dissolved in                                              The                                     Sequence (P H.sub.2 O) (P CO.sub.2 + P H.sub.2 O) Space at STP 4 L                                                  Solution at STP                       __________________________________________________________________________      1. 103.21 mm of Hg 5.00 Psig (258.5 mm of Hg) 1.37 L (337 ppm) 2.25 L                                               (1104 ppm)                              2. 103.21 mm of Hg 14.75 Psig (762.6 of Hg) 5.83 L (1432 ppm) 5.04 L                                                (2477 ppm)                              3. 103.21 mm of Hg 29.00 Psig (1499.3 mm of Hg) 12.34 L (3031 ppm) 9.39                                             L (4614 ppm)                            4. 65.82 mm of Hg 5.00 Psig (775.5 mm of Hg) 6.45 L (1584 ppm) 8.04 L                                               (3950 ppm)                              5. 65.82 mm of Hg 4.00 Psig (206.8 mm of Hg) 1.28 L (114 ppm) 2.34 L                                                (1149 ppm)                              6. 65.82 mm of Hg 9.50 Psig (491.2 mm of Hg) 3.86 L (348 ppm) 3.38 L                                                (1660 ppm)                              7. 65.82 mm of Hg 14.00 Psig (723.8 mm of Hg) 5.98 L (469 ppm) 4.89 L                                               (2402 ppm)                              8. 65.82 mm of Hg 18.50 Psig (946.5 mm of Hg) 8.09 L (1987 ppm) 6.40 L                                              (3144 ppm)                              9. 65.82 mm of Hg 27.50 Psig (1421.8 mm of Hg) 12.32 L (3026 ppm) 9.41                                              L (4622 ppm)                            10. 52.16 mm of Hg 4.2 Psig (217.1 mm of Hg) 1.52 L (373 ppm) 2.10 L                                                (1032 ppm)                              11. 52.16 mm of Hg 13.50 Psig (698.0 mm of Hg) 5.95 L (1461 ppm) 4.92 L                                             (2417 ppm)                              12. 52.16 mm of Hg 26.80 Psig (385.6 mm of Hg) 12.29 L (3018 ppm) 9.45                                              L (4639 ppm)                          __________________________________________________________________________     *Margin of error is less than 3% of fullscale 0-30 psig) as per NIST          calibration standard.                                                         **Estimated solution temperature based on runs 1 and 2.                       ***Powdered product not packaged in PVA film, but added directly to heate     water.                                                                   

EXAMPLE 5

A field test was conducted wherein drain cleaners and compositionsaccording to the present invention were applied in a quick servicerestaurant soft drink station drain system clogged with polymericbacterial cellulose. The enzymatic aqueous solutions were prepared byadding a dry enzymatic detergent drain cleaner directly to the drains inneed of treatment, followed by hot water, and allowing the resultingenzymatic detergent solution to develop on the surface of the cellulosedeposits in the drain. By substantially sealing the drain at the pointof application, the rapid generation of carbon dioxide gas and foamformed by the water contacting the dry ingredients forced the productinto the drain system and into contact with the polymeric cellulosedeposits. Following treatment, the degraded cellulose deposits wereremoved by flushing the drains with water.

The test facility had two drink stations, one each at the front counterand the drive-through, serviced by a three inch PVC drain. The drain forthe drink stations serviced those stations only, terminating in a floordrain at each station. This branch fed into a drain header, which inturn fed into the main building drain.

Just upstream of the junction with the header, a two foot section of thepipe was sawed out before treatments began to determine the initialcondition of the exposed drain. The cellulose deposited in the pipeappeared in cross section to be a single mass, but when removed from thesawed out pipe, was found to comprise three elongated, rubbery,gelatinous, slimy semisolid masses. On the upstream side of the cutout,the mass of polymeric bacterial cellulose solidly filled half of thepipe, and the level rose to about two thirds downstream and beyond,severely reducing the capacity and flow of the drain.

The drain capacity was measured by pouring water from a bucket down thedrink station drains and measuring the output at the cutout with astopwatch. By this method, the measured flow rates varied up to sixtypercent, in part because of the backups caused by cellulose blockage inthe drink station drain lines. The average flow rate of 15-18 gallowsper minute indicated that the cellulose deposits severely impaired thefunction of this drain. When the observations and measurements werecompleted and recorded, the removed section was replaced with a sectionof clear PVC pipe to permit observation of the drain as it was beingtreated.

To test the compositions, a water delivery system was made from anordinary toilet plunger, a valve, and ordinary hose and pipe fittings.The plunger handle and dome were separated, and a hole was cut in theplunger dome, permitting a sealed connection of the dome interior and ahalf inch 90° pipe fitting. The fitting was in turn connected to theoutlet of an on-off valve, which had attached to its inlet a shortlength of hose with a standard female hose coupling, which in operationwas connected to a source of hot water.

To begin treatment, after initial observations were made and recorded,each drain was flushed with hot water. Next, the dry enzymatic detergentdrain cleaner product was poured directly into the drain system throughthe floor drains, and the water delivery system, with the hot watersource connected and the valve closed, was fitted to the floor drain toprovide the tightest seal possible. Achieving a close fit requiredslight modification of the floor drains to accommodate the plunger dome.With the delivery system in place, the valve was opened and hot waterwas forced through the valve and dome into the drain system. The contactof the hot water and the dry ingredients caused a reaction that producedlarge quantities of foam and carbon dioxide gas, which pressurized thedrain and forced the resultant enzymatic solution into the system, pastthe "J" bend watertrap, and into contact with the clogging cellulosedeposits.

The dry enzymatic detergent drain cleaner used for this field test wasprepared according to formula 102-44-0 in Example 3. The drain stationswere subjected to the following treatment regimen after the drinkstations were closed for the day:

    ______________________________________                                               Drink Station 1                                                                             Drink Station 2                                          ______________________________________                                        Day 1    Hot water flush 5 min.,                                                                       Hot water flush 5 min.,                                 followed by application followed by two consecu-                              of 6 ounces dry detergent tive applications of 4                              and 1 gallon of hot water ounces dry detergent and                            through the delivery sys- 1 gallon of hot water                               tem. through the delivery sys-                                                 tem.                                                                        Day 2 Hot water flush 5 min.; 4 Hot water flush 5 min.; 4                      ounces of detergent with ounces of detergent with                             1 gallon of hot water. 1 gallon of hot water.                                Day 3 Hot water flush 10 min.; Hot water flush 10 min.;                        4 ounces of detergent 4 ounces of detergent                                   with 1 gallon of hot wa- with 1 gallon of hot wa-                             ter. ter.                                                                    Day 4 4 ounces of detergent 4 ounces of detergent                              with 1 gallon of warm with 1 gallon of hot wa-                                water, followed by 6 ter.                                                     ounces of detergent with                                                      1 gallon of hot water.                                                       Day 5 No treatment. No treatment.                                             Day 6 6 ounces of detergent and 6 ounces of detergent and                      2 gallons hot of water. 1 gallon of hot water,                                 followed by 12 ounces of                                                      detergent and 2 gallons                                                       of hot water.                                                             ______________________________________                                    

Initial observation through the clear pipe on the first treatment dayrevealed that despite the removal of the section of cellulose the daybefore, the deposits held fast to the pipe wall upstream and downstreamof the cutout. The severe clogging caused by the cellulose caused abackup and overflow of foaming detergent at one of the drains duringtreatment. Immediately after the first treatment, the polymeric massremained intact, but loosened from the pipe wall and was observed tohave moved about two inches downstream into the clear section of pipe.

On the day after the first treatment, the cellulosic mass had moved sixinches further downstream, and brown particles of hydrolyzed materialscovered the bottom of the clear pipe. The second treatment partiallyhydrolyzed the cellulose deposits, which washed down the drain when itwas flushed with hot water. Accumulation of hydrolyzed materials wasseen in the transparent pipe after the second treatment. The effect ofthe enzymatic detergent solution on the cellulose deposits was quiteevident, as no backups occurred and the drain flow increasedsubstantially.

The day after the second treatment, the drain was observed initially tobe full of brown, particulate water, and drainage was very slow. Thedrains were treated and the particulate matter was thereby removed, butthe blockage persisted and caused some overflow during treatment.Further investigation revealed the slow drainage was caused by a clog ofunknown origin in the main drain outside of the building and not in thetreated section. Following removal of the outside blockage after thethird treatment, the water accumulation ceased, and the drain functionedvery effectively throughout the remainder of the test. Visual inspectionof the drain interior after completion of the test showed the completeremoval of the bacterial cellulose deposits effected by the treatments.

The effect of increasing the temperature and enzymatic detergent draincleaner concentration on foam generation was observed. Using the frontcounter drink station (Station 1) as the control facility, foamgeneration was observed in the clear pipe during the Day 4 treatmentdescribed in the Table above. Whereas combining four ounces of detergentwith one gallon of warm water at Station 1 filled the clear section halffull with foamy detergent solution, the subsequent treatment mixing sixounces of detergent and one gallon of hot water filled the clear sectionthree quarters full with foamy solution.

The effect of proportionally increasing the amounts of dry ingredientsand water on the extent of solution distribution within the drain alsowas observed. Using the drive-through drink station (Station 2) as thecontrol facility, the extent of solution distribution was observed inthe clear pipe during the Day 6 treatment described in the Table above.Whereas combining six ounces of dry detergent with two gallons of hotwater at Station 2 caused no foamy detergent solution to reach the clearsection, twelve ounces of dry detergent and two gallons of hot waterfilled the clear section one quarter full with foamy solution.

EXAMPLE 6

A second field test was run using the 102-44-0 formulation of Example 3and the water delivery system in a second quick service restaurant drainsystem, similar to the field test described in Example 5. The secondrestaurant had two drink stations, one at the front counter and one atthe drive-through, serviced by a four inch PVC drain. The drink stationdrains, with their accompanying floor drains, fed into a straightheader, which had a removable plug at the upstream end and emptied intothe main building drain downstream. The drive-through station drainentered the header farthest upstream, near the capped end, followed bythe front counter station drain, which fed into the header five feetfurther downstream. A third drain, from the floor of the front counter,entered the header even further downstream, but before the point wherethe header connected to the main drain. No other drains were serviced bythe header.

Initial observation of the untreated drain system revealed impairedfunction, i.e. slow drainage, in the drains feeding the header. Toassist in visual inspection of the drain pipe interior, the third drainwas disconnected from the header, and the remaining stub of pipeprojecting from the header was capped with an easily removed rubberboot. This point was labeled "Observation Point 1," and the removableplug at the far upstream end of the header was labeled "ObservationPoint 2." Visual inspection of the untreated drain interior at theobservation points revealed that significant polymeric bacterialcellulose had deposited in this drain system, filling half of the pipeat observation Point 2.

Treatments were made once daily after the close of business for fourconsecutive days. The method of application insofar as adding the dryenzymatic detergent drain cleaner to the drain, followed by hot waterprovided through the delivery system, was identical to the treatmentmethod used for the field test described in Example 5. The followingregimen was used on each station: the drink station floor drain wasflushed with hot water; the drain was charged with dry product, 4 ouncesfor Station No. 1. (front counter drink station) and 8 ounces forStation No. 2 (drive-through drink station); the delivery system wasfitted to the floor drain; and hot water (120°-140° F.) was delivered toeach drain using the delivery system, 1 gallon to Station No. 1 and 11/2gallons to Station No. 2, while as close a seal as possible wasmaintained between the delivery system and the floor drain inlet, toform the foaming, enzymatic detergent solution and to force it into thedrain and into contact with the cellulose deposits.

Twenty-four hours after the first treatment, partial hydrolysis wasevident from the slight distortion in the appearance of the cellulosedeposits from the initial observation. Twenty-four hours after thesecond treatment, the deposits had partially degraded and shrunkconsiderably, pulling away from the pipe wall filling only one third ofthe drain pipe at Observation Point 2, where it had previously been halffull. The third treatment shrank and loosened the degraded deposits evenmore, and by the close of business on the fourth day, prior to thefourth treatment, no deposits were visible in drain from eitherobservation point.

The results of the first and second field tests (Examples 5 and 6)confirmed the efficacy of the enzymatic detergent solution prepared bymixing dry enzymatic detergent drain cleaner product formulation102-44-0 with hot water in the drain pipe itself to remove heavypolymeric bacterial cellulose deposits in the sugar-rich soft drinkdrain environment, as well as the efficacy of the method using thedelivery system. Moreover, the second test (Example 6) confirmed thatthe physical disturbance of the cellulose caused by the removal of thepipe section in the first test (Example 5) was not necessary for theenzymatic solution to successfully attack bacterial cellulose deposits,since the deposits in the second test were not disturbed in any wayprior to treatment.

EXAMPLE 7

A third field test was run to determine the efficacy of an enzymaticdrain cleaning solution composition delivered to a clogged drain bydissolving dry product in hot water and pouring it into the drain. Asfor the previous tests described in Examples 5 and 6, the test facilityfor this field trial was a quick service restaurant drink station drainsystem, which served three drink stations (2 store front, 1drive-through), including floor and ice bin drains.

Each drink station, ice bin, and floor drain combination was serviced byits own two inch drain pipe, which fed into a drain header. Thedrive-through drain entered the header farthest upstream, near aclean-out plug on the header that was designated "Observation Point 1",followed first by the left store front drain ("Observation Point 2") andthen by the right store front drain. Through the points at which thedrive through and left store front drains entered it, the drain headerhad a two inch diameter. Between the left and right store front drains,the header expanded to four inches in diameter and passed through aplugged trap, labelled "Observation Point 3". After the trap, the rightstore front drain entered the header, which then passed to the maindrain.

Initial conditions were evaluated by visual inspection at the threeobservation points in the system. Little cellulose was found depositedupstream at the Observation Point 1, believed to be the result of arecent mechanical cleaning necessitated by chronic clogging of thisdrain. At the second observation point, the two inch drain pipe wasalmost full of bacterial cellulose deposits. At the third observationpoint, the four inch drain trap, a large clump of bacterial cellulosehad deposited.

The initial condition of the drink station drains was observed as well.The right store front drink station drain was significantly clogged, andthe drive-through floor drain contained significant bacterial cellulosedeposits. In addition, the drive-through drink station and ice bin drainwas completely blocked, providing no opportunity for the enzymaticcleaning solution to penetrate the deposits and to attack their surface.Accordingly, a short section of this drain was removed and partiallyopened manually before treatment to allow the cleaner to penetrate theblockage.

Following these preparations, the drink station drain system was treatedonce a day, fourteen times over a fifteen day period, with visualinspection after every third treatment. Drain cleaning solutions foreach station were prepared by dissolving 4 to 8 ounces of enzymaticdetergent drain cleaner formulation 102-44-0 with 1 to 11/2 gallons ofhot (approximately 140° F.) tap water in a 5 gallon bucket, and allowingthe resultant foam to collapse. Once the foam subsided, usually in about2 to 5 minutes, half of the cleaning solution was poured down the drinkstation drain and the other half into the ice bin drain, using a smallstyrofoam cup. The ice bin and drink station drains are joined and thentheir common drain enters the floor drain. Using this method, the drainsystem was subjected to the following treatment regimen:

    ______________________________________                                        Drive-Through  Left Store Front                                                                           Right Store Front                                 ______________________________________                                        Day 1 Drains flushed                                                                             Drains flushed                                                                             Drains flushed                                   with hot water; with hot water; with hot water;                               drains treated drains treated drains treated                                  with cleaning with cleaning with cleaning                                     solution prepared solution prepared solution prepared                         by mixing 4 by mixing 4 by mixing 4                                           ounces of dry ounces of dry ounces of dry                                     product with 1 product with 1 product with 1                                  gallon of hot gallon of hot gallon of hot                                     water. water. water.                                                         Day 2 Drains flushed Drains flushed Drains flushed                             with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 8 ounces of ing 8 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 1 gallon of hot                               water. water. water.                                                         Day 3 Drains flushed Drains flushed Drains flushed                             with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 8 ounces of ing 8 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 1 gallon of hot                               water. water. water.                                                         Day 4 Drains flushed Drains flushed Drains flushed                             with 11/2 gal- with 11/2 gal- with 11/2 gal-                                  lons of hot wa- lons of hot wa- lons of hot wa-                               ter; drains ter; drains ter; drains                                           treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 8 ounces of ing 8 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            11/2 gallons of 11/2 gallons of 11/2 gallons of                               hot water. hot water. hot water.                                             Day 5 Drains flushed Drains flushed Drains flushed                             with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 4 ounces of ing 4 ounces of ing 4 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 1 gallon of hot                               water. water. water.                                                         Day 6 Drains flushed Drains flushed Drains flushed                             with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 4 ounces of ing 4 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 1 gallon of hot                               water. water. water.                                                         Day 7 Drains flushed Drains flushed Drains flushed                             with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 4 ounces of ing 4 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 1 gallon of hot                               water. water. water.                                                         Day 8 No treatment. No treatment. No treatment.                               Day 9 Drains flushed Drains flushed Drains flushed                             with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 4 ounces of ing 4 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 11/2 gallons of                               water. water. hot water.                                                     Day 10 Drains flushed Drains flushed Drains flushed                            with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 4 ounces of ing 4 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 11/2 gallons of                               water. water. hot water.                                                     Day 11 Drains flushed Drains flushed Drains flushed                            with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 4 ounces of ing 4 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 11/2 gallons of                               water. water. hot water.                                                     Day 12 Drains flushed Drains flushed Drains flushed                            with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 4 ounces of ing 4 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 11/2 gallons of                               water. water. hot water.                                                     Day 13 Drains flushed Drains flushed Drains flushed                            with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 4 ounces of ing 4 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 11/2 gallons of                               water. water. hot water.                                                     Day 14 Drains flushed Drains flushed Drains flushed                            with 3 gallons of with 1 gallon of with 1 gallon of                           hot water; drains hot water; drains hot water; drains                         treated with treated with treated with                                        cleaning solution cleaning solution cleaning solution                         prepared by mix- prepared by mix- prepared by mix-                            ing 4 ounces of ing 4 ounces of ing 8 ounces of                               dry product with dry product with dry product with                            1 gallon of hot 1 gallon of hot 11/2 gallons of                               water. water. hot water.                                                     Day 15 Drains flushed Drains flushed Drains flushed                            with 3 gallons of with 11/2 gal- with 1 gallon of                             hot water; drains lons of hot wa- hot water; drains                           treated with ter; drains treated with                                         cleaning solution treated with cleaning solution                              prepared by mix- cleaning solution prepared by mix-                           ing 4 ounces of prepared by mix- ing 8 ounces of                              dry product with ing 4 ounces of dry product with                             1 gallon of hot dry product with 11/2 gallons of                              water. 11/2 gallons of hot water.                                              hot water.                                                                ______________________________________                                    

Twenty-four hours after the third treatment, the drains were inspectedat the observation points identified above. The two inch drain pipe atObservation Points 1 and 2 was completely clear of any cellulosematerial. At Observation Point 3, the four inch trap, about 7 gallons ofwaste material composed of brown particulates, oily material, and longstrands of bacterial cellulose was drained from the drain system afteropening the plug. Following removal of this material, the trap also wasclear of any deposits. Close inspection of the cellulose recovered fromthe trap revealed that the material was degrading.

In addition to the above treatments and observations, the performance ofeach of the two store front drains was monitored through the course ofthe test. The results of this investigation are set forth in the Tablethat follows:

    ______________________________________                                        Time To Drain 11/2 Gallons Of Treatment Solution                                Treatments                                                                    Completed Store Front Left Store Front Right                                ______________________________________                                        4          Approx. 2 min. Approx. 15 min.                                       8 Approx. 2 min. Approx. 5 min.                                               9 Approx. 2 min. Approx. 5 min.                                               10 Approx. 2 min. Approx. 4 min.                                              11 Approx. 2 min. Approx. 4 min.                                              12 Approx. 2 min. Approx. 31/2 min.                                           13 Approx. 2 min. Approx. 3 min.                                              14 Approx. 13/4 min. Approx. 21/3 min.                                      ______________________________________                                    

This data confirms that a substantial cellulose blockage was present inthe right store front drink station drain at the beginning of this fieldtest, which blockage was significantly if not completely eliminatedafter treatment with the enzymatic cleaning solution. This field testconfirmed that the enzymatic drain cleaning solution functionedeffectively when applied in the described dissolve and pour method,requiring no special delivery system or conditions.

EXAMPLE 8

A fourth field test was performed to evaluate the efficacy of dryenzymatic detergent drain cleaner product formulations 102-44-0 and102-51-4 to remove fresh cellulose deposits that had grown in previouslytreated drain systems. For this field test, the drain system treated inthe first field test described in Example 5 was revisited.

In the two months that elapsed from that earlier field test, significantand substantial quantities of fresh cellulose had grown in the drainsystem, filling approximately half of the diameter of the clear pipeinstalled for observation in the first field test. In addition, a drainserving the restaurant's three-compartment sink was very slow andbelieved to be clogged with bacterial cellulose deposits.

Each drink station drain was treated at the close of business for threeconsecutive days using the dissolve and pour method described in Example7. Thus, the drain system was subjected to the following treatmentregimen:

    ______________________________________                                                 Store Front  Drive Through                                           ______________________________________                                        Day 1      Drains flushed Drains flushed                                         with 2 gallons of with 2 gallons of                                           hot water; drains hot water; drains                                           treated with treated with                                                     cleaning solution cleaning solution                                           prepared by mixing prepared by mixing                                         8 ounces of dry 8 ounces of dry                                               product formula product formula                                               102-44-0 with 11/2  102-44-0 with 11/2                                        gallons of hot gallons of hot                                                 water. water.                                                                Day 2 Drains flushed Drains flushed                                            with 2 gallons of with 2 gallons of                                           hot water; drains hot water; drains                                           treated with treated with                                                     cleaning solution cleaning solution                                           prepared by mixing prepared by mixing                                         4 ounces of dry 4 ounces of dry                                               product formula product formula                                               102-51-4 with 102-51-4 with                                                   11/2 gallons of 11/2 gallons of                                               hot water. hot water.                                                        Day 3 Drains flushed Drains flushed                                            with 2 gallons of with 2 gallons of                                           hot water; drains hot water; drains                                           treated with treated with                                                     cleaning solution cleaning solution                                           prepared by mixing prepared by mixing                                         4 ounces of dry 4 ounces of dry                                               product formula product formula                                               102-51-4 with 102-51-4 with                                                   11/2 gallons of 11/2 gallons of                                               hot water. hot water.                                                      ______________________________________                                    

Twenty-four hours after the first treatment, the cellulose build-up hadbecome loosened and swelled due to partial hydrolysis, and forty-eighthours after the first treatment, the cellulose build-up appearedshrunken. The third treatment was initiated by adding 5 gallons of hotwater to the drive through ice bin drain, after which the degradedbacterial cellulose deposits were observed through the clear section tohave begun moving down towards the main drain. Five additional gallonsof hot water were poured down the sink, causing the bacterial cellulosedeposits to move further and to completely clear the drain system. Thistest confirmed that dry formulations 102-44-0 and 102-51-4 wereeffective to clear fresh bacterial cellulose build-up using the dissolveand pour method. Further, it was confirmed that this treatmenthydrolyzed the bacterial cellulose to a point that running hot waterdown the drain would successfully flush the deposits from the systemfollowing treatment.

What is claimed is:
 1. A method of removing or preventing bacterialcellulose deposits in an aqueous system comprising:(a) forming anaqueous solution by adding together an enzymatic detergent drain cleanerconsisting essentially of:(1) about 0.015% to about 20% by weight of anacid cellulase enzyme having hydrolytic activity specific toβ-glucosidic bonds; (2) about 1% to about 70% by weight of a watersoluble carbonate salt; (3) about 1% to about 70% by weight of a watersoluble acid that reacts in an aqueous medium at standard temperatureand pressure with the carbonate salt to form at least 100 ppm of carbondioxide that dissolves in the aqueous medium; (4) about 0.1% to about10% by weight of a surfactant; and (5) about 0.05% to about 5% by weightof a thickening agent, with an aqueous medium; and (b) contacting anaqueous system in recognized need of such removal or prevention with theaqueous solution for a sufficient time to at least partially hydrolyzethe bacterial cellulose, whereby the partially hydrolyzed bacterialcellulose is removed from said aqueous system.
 2. The method of claim 1,wherein the aqueous solution has a temperature of up to about 60° C. anda pH of about 2 about
 7. 3. The method of removing or preventingbacterial cellulose deposits in an aqueous system according to claim 1,wherein the aqueous solution is formed by adding together an enzymaticdetergent drain cleaner consisting essentially of:(1) about 0.05% toabout 15% by weight of an acid cellulase enzyme having hydrolyticactivity specific to β-glucosidic bonds; (2) about 10% to about 50% byweight of a water soluble carbonate salt; (3) about 10% to about 50% byweight of a water soluble acid that reacts in an aqueous medium atstandard temperature and pressure with the carbonate salt to form atleast 100 ppm of carbon dioxide that dissolves in the aqueous medium;(4) about 0.5% to about 8% by weight of a surfactant; and (5) about 0.1%to about 4% by weight of a thickening agent, with an aqueous medium. 4.The method of claim 3, wherein the aqueous solution has a temperature of40° C. to about 55° C. and a pH of about 3.5 to about 6.5.
 5. The methodof removing or preventing bacterial cellulose deposits in an aqueoussystem according to claim 1, wherein the aqueous solution is formed byadding together an enzymatic detergent drain cleaner consistingessentially of:(1) about 0.5% to about 10% by weight of an acidcellulase enzyme having hydrolytic activity specific to β-glucosidicbonds; (2) about 10% to about 50% by weight of an acid selected from thegroup consisting of sulfamic acid and citric acid; (3) about 30% toabout 50% by weight of sodium bicarbonate; (4) about 1% to about 10% byweight of sodium carbonate; (5) about 2% to about 10% by weight of apowdered sodium dodecyl benzene sulfonate surfactant; and (6) about 1%to about 5% by weight of a crosslinked polyacrylic acid thickeningagent, with an aqueous medium.
 6. The method of claim 5, wherein theaqueous solution has a temperature of about 40° C. to about 50° C. and apH of about 4 to about 5.5.
 7. The method of removing or preventingbacterial cellulose deposits in an aqueous system according to claim 1,wherein the aqueous solution is formed by adding together an enzymaticdetergent drain cleaner consisting essentially of:(1) about 6% by weightof an acid cellulase enzyme having hydrolytic activity specific toβ-glucosidic bonds; (2) about 43% by weight of citric acid; (3) about40% by weight of sodium bicarbonate; (4) about 5% by weight of sodiumcarbonate; (5) about 10% by weight of a powdered sodium dodecyl benzenesulfonate surfactant; and (6) about 1% by weight of a crosslinkedpolyacrylic acid thickening agent, with an aqueous medium.
 8. The methodof claim 7, wherein the aqueous solution has a temperature of about 40°C. to about 50° C. and a pH of about 4 to about 5.5.
 9. The method ofremoving or preventing bacterial cellulose deposits in an aqueous systemaccording to claim 1, wherein the aqueous solution is formed by addingtogether an enzymatic detergent drain cleaner consisting essentiallyof:(1) about 4% by weight of an acid cellulase enzyme having hydrolyticactivity specific to β-glucosidic bonds; (2) about 40% by weight ofsulfamic acid; (3) about 40% by weight of sodium bicarbonate; (4) about5% by weight of sodium carbonate; (5) about 10% by weight of a powderedsodium dodecyl benzene sulfonate surfactant; and (6) about 1% by weightof a crosslinked polyacrylic acid thickening agent, with an aqueousmedium.
 10. The method of claim 9, wherein the aqueous solution has atemperature of about 40° C. to about 50° C. and a pH of about 4 to about5.5.
 11. A method of removing or preventing bacterial cellulose depositsin an aqueous system comprising the step of contacting an aqueous systemin recognized need of such removal or prevention with a compositionconsisting essentially of an aqueous solution of an acid cellulaseenzyme present in an amount of at least about 0.015 g/l and havinghydrolytic activity specific to β-glucosidic bonds, and said aqueoussolution having a dissolved carbon dioxide concentration of at leastabout 100 ppm at standard temperature and pressure, for a sufficienttime to at least partially hydrolyze the deposits, whereby the partiallyhydrolyzed bacterial cellulose is removed from the aqueous system. 12.The method of removing or preventing bacterial cellulose depositsaccording to claim 11, said composition consisting essentially of anaqueous solution of an acid cellulase enzyme present in an amount of atleast about 0.15 g/l and having hydrolytic activity specific toβ-glucosidic bonds, and said aqueous solution having a dissolved carbondioxide concentration of at least about 300 ppm at standard temperatureand pressure.
 13. The method of removing or preventing bacterialcellulose deposits according to claim 11, said composition consistingessentially of an aqueous solution of an acid cellulase enzyme presentin an amount of at least about 0.30 g/l and having hydrolytic activityspecific to β-glucosidic bonds, and said aqueous solution having adissolved carbon dioxide concentration of at least about 500 ppm atstandard temperature and pressure.
 14. The method of removing orpreventing bacterial cellulose deposits according to claim 11, whereinsaid carbon dioxide concentration is provided at least in part by asystem for enriching the aqueous system with dissolved carbon dioxide,comprising a water soluble carbonate salt selected from the groupconsisting of carbonate salts of alkali metals, carbonate salts ofalkaline earth metals, ammonium carbonate, and ammonium bicarbonate anda water soluble acid selected from the group consisting of formic acid,acetic acid, hydroxyacetic acid, propionic acid, butyric acid, valericacid, caproic acid, lauric acid, palmitic acid, stearic acid, citricacid, sebacic acid, gluconic acid, tartaric acid. succinic acid, malicacid, uric acid, polymaleic-acrylic acids, acrylic acids, polyacrylicacids, maleic acid, benzoic acid, fumaric acid, isophthalic acid,terephthalic acid, suberic acid, pimelic acid, malonic acid, glutaricacid, adipic acid, lactic acid, hydrochloric acid, hydrofluoric acid,hydrobromic acid, hydroiodic acid, sulfuric acid, sulfamic acid,sulfurous acid. phosphoric acid, phosphorous acid, polyphosphoric acid,hypophosphorous acid, and boric acid, that, under aqueous conditions.reacts with the salts to form carbon dioxide that dissolves in theaqueous system.said composition further comprising at least about 0.25gl/l of a surfactant and at least about 0.15 g/l of a thickener, whereinsaid aqueous solution has a temperature of up to about 60° C. and a pHof about 2 to about
 7. 15. The method of removing or preventingbacterial cellulose deposits according to claim 14, wherein said aqueoussolution has a temperature about 40° C. to 55° C. and a pH of about 3.5to about 6.5.
 16. The method of removing or preventing bacterialcellulose deposits according to claim 15, wherein said aqueous solutionhas a temperature about 40° C. to 50° C. and a pH of about 4 to about5.5.
 17. The method of removing or preventing bacterial cellulosedeposits according to claim 14, wherein glucono-δ-lactone, sodiumbisulfate, or sodium bisulfite is used in place of the water solubleacid.
 18. The method of removing or preventing bacterial cellulosedeposits according to claim 15, wherein glucono-δ-lactone, sodiumbisulfate, or sodium bisulfite is used in place of the water solubleacid.
 19. The method of removing or preventing bacterial cellulosedeposits according to claim 16, wherein glucono-δ-lactone, sodiumbisulfate, or sodium bisulfite is used in place of the water solubleacid.